Interlocking sheet metal and attachment nut construction



Jan, 12, 1954 J. T. TRUMBLE 2,665,730

INTERLOCKING SHEET METAL AND ATTACHMENT NUT CONSTRUCTION Filed Feb. '25, 1950 3/ 27 27 3/ /0 3/ I7 1/ )f f 29 3m tor I en 1 25 5 4 Z6 Lick 1 79402 6X? atttornegs Patented Jan. 12, 1954 OFFICE INTERLOCKING SHEET METAL AND AT- TACHMENT NUT CONSTRUCTION John T. Trumble, Detroit, Mich.

Application February 25, 1950, Serial No. 146,205

1 Claim.

This invention relates to fasteners and, in par ticular, to attachment nuts for connecting bolts or screws to sheet metal.

In industries which are large users of stamped sheet metal parts, such as the automobile body industry, attachment nuts have come into wide use to provide screw threads where the thickness of the sheet metal is itself inadequate for threading. Such nuts which provide these screw threads are frequently welded to the sheet metal or clinched thereto, these being termed weld nuts and clinch nuts respectively. When other parts are to be attached to the sheet metal parts, such as door or other body stampings of an automobile body, screws or bolts are inserted through these parts and beyond them are threaded into the attachment nuts. Such prior weld nuts and clinch nuts, however, add considerably to the time and labor of attaching these parts, and consequently make a considerable addition to the cost of nianu facture. The present invention provides an attachment nut which involves no welding, deformation or mutilation of the nut, nor are special tools of any sort required for its installation,

One object of this invention is therefore to pro vide an interlocking sheet metal and attachment nut structure which permanently attaches the nut without requiring welding or deformation of the nut or special tools for its installation, the nut being grooved and merely slipped into upstruck portions at the opposite sides of an aperture formed in the sheet metal member at the time and in the same operation in which it is stamped out in a stamping press.

Another object is to provide an interlocking sheet metal and attachment nut structure of the foregoing character in which the height of the upstruck portions above the plane of the surrounding sheet metal is made a predetermined dimension in relation to the thickness of the ridge on the nut and the width of the groove so that the nut does not slide loosely into its place on the sheet metal member but must be forced or sprung into place sufliciently to cause it to snap into position and remain there without danger of subsequent dislodgment while the sheet metal part is in service on an automobile body or elsewhere.

Another object is to provide an interlocking sheet metal and attachment nut structure of the foregoing character wherein the upstruck portions consist of flanges extending along and above the opposite sides and optionally one end of a rectangular aperture, and wherein the sides of the nut preferably overhang the side walls of the upstruck flanges, so that these side walls and not the flanges sustain the load imposed by the screw threaded into the nut.

In the drawings:

Figure l is a front elevation of a portion of a sheet metal member having an aperture with upstruck opposite sides and one end, ready to receive an attachment nut, according to one form of the invention;

Figure 2 is a horizontal section taken along the line 2-2 in Figure 1;

Figure 3 is a vertical section taken along the line 3-3 in Figure 1;

Figure 4 is a front elevation of the sheet metal member portion of Figure 1, with an attachment nut partially inserted;

Figure 5 is a horizontal section taken along the line 5--5 in Figure 4;

Figure 6 is a vertical section, with the nut in side elevation, taken along the line 5 in Figure 4;

Figure 7 is a front elevation similar to Figure 4, but with the attachment nut completely inserted and locked in position;

Figure 8 is a horizontal section taken along the line 8-8 in Figure 7;

Figure 9 is a vertical section, with the nut in side elevation, taken along the line in Figure '7;

Figure 10 is a rear perspective view of the attachment but shown in Figures 4 to 8 inclusive;

Figure 11 is a horizontal section through the interlocking sheet metal and attachment nut structure of Figures 1 to 10 inclusive, showing another sheet metal member attached thereto by means of a threaded fastener;

Figure 12 is a front elevation of a portion of a modified sheet metal member having an aperture with upstruck opposite sides only;

Figure 13 is a horizontal section taken along the line I3--I3 in Figure 12;

Figure 14 is a vertical section taken along the line "-44 in Figure 12;

Figure 15 is a front elevation of the sheet metal member portion of Figure 12, with the attach ment nut completely inserted and locked in position; d

Figure 16 is a horizontal section taken along the line Iii-46 in Figure 15.

Referring to the drawings in detail, Figure '7 shows an interlocking sheet metal and attachment nut structure, generally designated Ii), according to one form of the invention as including an upstruck apertured sheet metal memher, generally designated II, and an attachment nut, generally designated I2, interlocked therewith, as described below. The sheet metal member II (Figures 1, 2 and 3), of which only one portion is shown, may consist, for example, of an automobile body stamping to which another member is to be attached by one or more attachment screws. The sheet metal member I I shown in Figure l for this purpose is provided with an approximately rectangular aperture I3 formed by striking up side flanges I4 having an interconnecting end flange I5, these flanges being spaced above the level of the surrounding sheet metal member II to form an upstruck nut receiving portion I6 by side walls I! and an end wall I8 respectively. The flanges I4 and I are separated from one another by a three-sided rectangular cutaway portion I9 having parallel edges and an end edge H. The foregoing construction thus results in a recess 22 of rectangular outline for receiving the nut I2 and having three of its sides bounded by the side walls I! and end wall I8, and its fourth side open, with the free aperture edge 23 extending across the aperture I3 in front of the side flange ends 24 and spaced slightly Way from them (Figure 1), in order to facilitate insertion of the nut l2.

The attachment nut I2 (Figure 10) has a rectangular body 25 containing a threaded hole 26 and having rectilinear slots 2'! cut or otherwise formed in its opposite sides 29. These sides 29 are preferably wider than the aperture I3 so as to overhang the side walls I! beneath the side flanges I4, whereby the walls I! sustain the load. The formation of the slots 2'I results in the formation of a neck portion 33 from which flange 3I extend outward in opposite directions and terminating in the unflanged ends 32 of the nut body 25. The width of the lower portion of the nut between the edges of the flanges 3I is preferably less than the width of the main portion of the nut between its opposite sides 29 so as to facilitate insertion of the nut I2. The width of the slots 21 is correlated during design and manufacture with the thickness of the sheet metal member II, and the heights of its flanges I4 above the adjacent sheet metal member II such that the nut I2 may be inserted therein at a relatively small acute angle (Figure 6) and manently into a locked position.

Prior to the use of the invention, the upstruck flanges I4 and I5 and aperture I3 are preferably formed during the same stamping operation in the stamping press which shapes the member II into its desired form, as stated above. To install the grooved nut I2 in the upstruck portion I5 of the sheet metal member II, one of its unflanged ends 32 is presented to the ends 24 of the flanges I4 and the slots 21 directed to receive the flanges I4 (Figures 4 and 6). The nut I2 is then pushed obliquely into the aperture I3 and recess 22 with its flanges 3I below the sheet metal member flanges I4. The pressure exerted by the operator on the opposite end 32 from that presented to the flanges I4 (Figure 6) causes the flanges and the sheet metal adjacent the free edge 23 of the aperture I3 to spring slightly in an amount sufficient to permit the complete entry of the nut I2. The latter, as soon as it passes over the edge 23, snaps into its permanent position shown in Figures '7 to 9 inclusive, and the temporarily displaced 4 metal of the flanges I4 and sheet metal portion I6 return to their original position.

With the nut I2 completely installed in this manner, it is prevented from becoming accidentally dislodged by the edge 2| of the end flange I5 engaging one end 32 of the nut I2, whereas the other end 32 engages the free edge 23 of the aperture I3. The sheet metal member II, with its various attachment nuts I2, can thus be assembled in this manner before it is brought into assembly with the other parts to which it is attached, such as, for example, the body of an automobile. On the assembly line, the workman can then easily and quickly attach other members 33 (Figure 11) to the sheet metal member II merely by inserting a screw 34 through a previously drilled hole 35 and threads the shank of the screw 34 into the threaded hole 26 in the nut I2. This may be done, for example, by a power-driven magazine screw driver with great rapidity and with low cost of labor. The operator inserts as many screws 34 as there are sheet metal and attachment nut structures Ill, the member 33 in this manner being firmly and permanently secured in position in a way which is especially well adapted to modern high speed assembling line manufacturing methods. Since the sides 2e overhang the side walls ll of the side flanges I4, the side walls I! and not the flanges I4 sustain the major portion of the load imposed by the screws 34.

The modified interlocking sheet metal and attachment nut structure, generally designated 40, shown in Figures 12 to 16 inclusive is generally similar to the structure I0 shown in Figures 1 to 9 inclusive, and corresponding parts are correspondingly designated. In the modification of Figures 12 to 16 inclusive, the attachment nut I2 is the same as in Figures 1 to 9 inclusive and the side flanges I4 at opposite sides of the aperture I3 also are similarly formed. In the sheet metal member II of Figures 12 to 14 inclusive, however, the bridging flange I5 is omitted and the side flanges I4 are the same at both ends 24. Furthermore, the recess 22 is open at its opposite ends 23 instead of being closed at one end by the bridging flange I5 and end wall I8 thereof. The open-ended upstruck portion generally designated 42 has the advantage of permitting the nut I2 to be inserted from opposite directions at some sacrifice in struc tural strength.

The installation of the nut I2 in-the upstruck portion 42 of the sheet metal member M is generally similar to the installation previously explained in connection with Figures 1 to 9 inclusive, hence requires no repetition. The attachment of an additional member by means of fasteners is also substantially identical with that described in connection with Figure 11. When the nut 12 has been inserted and snapped into position, as shown in Figures 15 and 16, the flanges I4 and edges I3 which have been slightly sprung out of position during installation, spring back to their original positions and the edges 23 serve as stops for the opposite ends 32 of the nut I2 and prevent it from coming out.

What I claim is:

In an interlocking fastener, a sheet metal member having a rectangular opening provided with upstruck side flanges formed with inturned guide projections, a bridge flange upstruck from said opening connecting the side flanges at one end thereof, said bridge flange being provided with an inturned guide projection connecting said first mentioned guide projections, the opposite ends of the upstruck side flanges and inturned guide projections terminating a, slight distance from the edge of said rectangular opening to provide a restricted entrance slot beneath the end of each inturned guide projection and the edge of said opening, and a threaded fastener conforming in shape to said rectangular opening having inwardly directed slots along the full length of a pair of opposite side edges thereof for receiving said guide projections, said slots being cut to form inner and outer sets of opposed flanges, the inwardly directed slots being of a thickness slightly greater than the thickness of said inturned guide projections and the inner flanges of said fastener being slightly thicker than the distance between the internal guide projections and said sheet metal member, so that the fastener can be seated by JOHN T. TRUMBLE.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,062,635 Clements May 27, 1913 1,579,875 Lundberg Apr. 6, 1926 1,872,385 Andren Aug. 16, 1932 2,029,089 Weiranch Jan. 28, 1936 2,477,429 Swanstrom et al. July 26, 1949 

